Public health and components of particulate matter: The changing assessment of black carbon

1. Public health and components of particulate matter:The changing assessment of black carbon Comments on the 2014 Critical Review Dan Greenbaum, President Health Effects Institute AWMA Meeting Long Beach California June 25, 2014 Trusted Science ● Cleaner Air ● Better Health

2. An Excellent Compendium • What is Black Carbon? • Discusses pros and cons of different measurements • An appropriate focus on how to measure exposure • A wide-ranging review of largely short term epidemiology and toxicology results

3. An appropriate focus on diesel, with acknowledgement of the recent improvementsData from HEI’s Advanced Collaborative Emissions Study (ACES):Evaluating Emissions of 2007 – 2010 Advanced Technology Diesels Dramatic Reductions (Khalek, et al JAWMA 2011) - 98% reduction in mass- 90% - 99% reduction in Ultrafine Particles- Substantial reduction in carbon particles

4. Important identification of developing country sourcese.g. many sources of BC in Asia And significant PM effects (GBD 2010) 3.2 million premature deaths (2/3 in Asia)

5. A Key Challenge: Long Term Effects • Most public health and cost-benefit assessments rely on long-term studies • The Critical Review cites a wide range of studies • But only two major cohort long term studies (Lipfert Veterans cohort; Brunekreef Dutch cohort) • HEI’s Traffic Effects Review (2010) found suggestive (not causal) evidence of longer term CVD mortality • Cohorts report much larger relative risks • Likely to be different biological mechanisms

6. A Key Challenge:Placing BC in the larger PM Context • BC important, but clearly not the only component of PM • And BC exists with a number of gases as well • The authors correctly suggest applying EPA’s “causality” framework • But do not quote EPA’s own conclusion: “Overall, the results indicate that many constituents of PM can be linked with differing health effects and the evidence is not yet sufficient to allow differentiation of those constituents or sources that are more closely related to specific health outcomes.” (Emphasis Added; Final EPA PM ISA December 2009)

7. Critical Review: Some things missing… • The latest science on Black Carbon • E.g. Bond et al JGR May 2013 • HEI’s NPACT Studies (October 2013) • Lippmann M, Chen L-C, Gordon T, Ito K, Thurston GD. 2013. HEI Research Report 177. National Particle Component Toxicity (NPACT) Initiative: Integrated Epidemiologic and Toxicologic Studies of the Health Effects of Particulate Matter Components • Vedal S, Campen MJ, McDonald JD, Kaufman JD, Larson TV, Sampson PD, Sheppard L, Simpson CD, Szpiro AA. HEI Research Report 178. National Particle Component Toxicity (NPACT) Initiative Report on Cardiovascular Effects.

8. Bond et al June 2013- The most comprehensive review to date on sources and transport of BC…- Understanding has changed substantially since 2004

9. NPACT: A Systematic and Integrated Approach : ToxicologyNYU = 4 (+ 1) sites, 6-month CAPS exposures ApoE -/- mouse LRRI = Albuquerque, 50-day defined exposures ApoE -/- mouse Seattle: Strong wood smoke signal, little sulfate, Tuxedo, NY: Rural, little traffic, strong sulfate East Lansing: Suburban mix of sulfates, vehicles Irvine: Few sulfates, strong traffic (gasoline) Albuquerque (LRRI): Lab studies of vehicles, secondary sulfate, nitrate, road dust New York City: Strong traffic (diesel) and sulfates

10. NPACT: Long Term Epidemiology in Over 100 Cities

11. Lippmann – animal inhalation (Chen) Strongest CVD Effects in East Coast/Midwest Cities (with SO4 and Traffic) Short-term Long-term

12. Lippmann – ACS cohort (Thurston) without covariates with covariates Results for EC and Traffic were sensitive to the inclusion of covariates in the analyses Note that only significant and marginal associations are shown

13. Vedal toxicology (Campen) (A combination of solid particles and MV gases?)

14. Vedal – MESA cohort PM2.5, Sulfur, and OC Associated with Carotid Intima Media Thickness (NOT EC or silicon) No significant associations with Coronary Artery Calcium

15. Vedal – WHI cohort PM2.5, Sulfur, and OC Associated with CVD Events (NOT EC or silicon) Vedal – WHI-OS cohort

16. Coherence of NPACT Study Findings

17. NPACT Conclusions • The NPACT studies are the most systematic effort to combine epidemiologic and toxicologic analyses of the health effects of PM components to date • The studies found associations between health effects and sulfate particles (primarily from coal combustion) and, to a somewhat lesser extent, traffic sources … but the HEI NPACT Panel concluded that the studies do not provide compelling evidence that any specific source, component, or size class of PM may be excluded as a possible contributor to PM toxicity.

18. Concluding Thoughts on the Review… • A Very Good Job… • Large number of studies reviewed • Careful attempt to look at how exposure estimated • Some Challenges as well • Few Long Term Studies • Not Placed in broader PM context • Key studies missing • Bond et al June 2013 • NPACT October 2013

19. Thank You! dgreenbaum@healtheffects.org